The present invention relates to a vane compressor for use in air conditioning systems for vehicles, and more particularly to a variable-displacement vane compressor capable of varying the volume of discharge under the control of electromagnetic forces.
Various methods have been practiced for controlling the volume of discharge from vane compressors. One such method is to restrict the volume of a gas to be compressed at a suction side of the compressor. According to another control process, discharged gas is fed back to the suction side through a bypass passage. These prior control arrangements are disadvantageous, however, in that the work performed by the compressor remains substantially the same irrespective of whether the volume of the discharged gas is increased or decreased. The result is often wasteful consumption of power.
The specification of Japanese Utility Model Publication No. 50-15216, entitled "Rotary Compressor", discloses vanes of a ferromagnetic material which are retractable under electromagnetic forces back into an inoperative position. The disclosed compressor is merely designed to assume either a position in which a compressed fluid is discharged in a full volume or a position in which no compressed fluid is discharged. Thus the compressor fails to limit the volume of discharge to a desired degree under variable-displacement control.